US5196298A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic developing solution containing an ascorbic acid derivative
Assignee: Agfa Gevaert NV
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Filing: 1992-02-05
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Granted: 1993-03-23
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Expires: 2012-02-05
Abstract
Abstract A photographic developing solution for immersion development is disclosed showing a pH of at least 12.0 and containing more than 0.4 moles/liter of a sugar derivative, or an alkali metal salt thereof, corresponding to general formula (I): ##STR1## wherein X represents an oxygen atom or an imino group, and n represents a positive integer from 1 to 4, and R represents a hydroxy group when n is 1, and R represents a hydroxy group or a hydrogen atom when n is 2 to 4. Preferred sugar derivatives according to the present invention are l-ascorbic acid and iso-ascorbic acid. In a most preferred embodiment there are substantially no other developing agents and no sulphite ions present. When developing a graphic arts photographic material lith quality is obtained. The disposal of depleted solutions can be performed in an ecologically safe way.
Inventors
- 👤 Pascal F. Meeus
- 👤 Peter M. Willems
- 👤 Gino L. De Rycke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:23
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/29; G03C5/30
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
81 words
Photographic developing solution for immersion development showing a pH of at least 12.0 and containing more than 0.45 moles/liter of a sugar derivative, or an alkali metal salt thereof, corresponding to general formula (I): ##STR4## wherein X represents an oxygen atom or an imino group, and n represents a positive integer from 1 to 4, and R represents a hydroxy group when n is 1, and R represents a hydroxy group or a hydrogen atom when n is 2 to 4.
Claim 2
Dependent Claim
81 words
Photographic developing solution for immersion development showing a pH of at least 12.0 and containing more than 0.45 moles/liter of a sugar derivative, or an alkali metal salt thereof, corresponding to general formula (I): ##STR4## wherein X represents an oxygen atom or an imino group, and n represents a positive integer from 1 to 4, and R represents a hydroxy group when n is 1, and R represents a hydroxy group or a hydrogen atom when n is 2 to 4.
Claim 3
Dependent Claim
17 words
Photographic developing solution according to claim 1 wherein said sugar derivative is l-ascorbic acid or iso-ascorbic acid.
Claim 4
Dependent Claim
23 words
Photographic developing solution according to claim 1, wherein the concentration of said sugar derivative is comprised between 0.45 and 0.90 moles per liter.
Claim 5
Dependent Claim
15 words
Photographic developing solution according to claim 1, wherein the pH ranges from 12.3 to 13.5.
Claim 6
Dependent Claim
16 words
Photographic developing solution according to claim 1, which contains no substantial amount of another developing agent.
Claim 7
Dependent Claim
15 words
Photographic developing solution according to claim 1, which contains no substantial amount of sulphite ions.
Claim 8
Dependent Claim
24 words
Photographic developing solution according to claim 1, which further contains an alkali bromide in a concentration ranging from 0.1 to 0.4 moles per liter.
Claim 9
Dependent Claim
13 words
Photographic developing solution according to claim 1, which further contains a heterocyclic stabilizer.
Claim 10
Dependent Claim
17 words
Photographic developing solution according to claim 8 wherein said heterocyclic stabilizer in a mercapto-group containing heterocyclic stabilizer.
Claim 11
Dependent Claim
30 words
Photographic developing solution according to claim 9 wherein said heterocyclic stabilizer containing a mercapto-group is 1-phenyl-5-mercaptotetrazole and said stabilizer is present in a concentration ranging from 20 to 250 mg/l.
Claim 12
Dependent Claim
24 words
Method for developing an image-wise exposed photograpic material comprising the steps of immersing said material in a photographic developing solution according to claim 1.
Claim 13
Dependent Claim
18 words
Method according to claim 11 wherein said photographic material is a graphic arts material containing a chlorobromide emulsion.
Claim 14
Dependent Claim
23 words
Method according to claim 11, wherein the concentration of said sugar derivative and the pH is maintained at a constant value by replenishment.
References Cited (Backward Citations)
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US3730727A
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US3826654A
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US5098819A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-03-22 | 1996-09-21 | 1997-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-03-22 | 2000-09-21 | 2001-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-03-22 | 2004-09-21 | 2005-03-23 | $7700.00 | Window Closed / Lapsed |